IC-tag read-write apparatus

ABSTRACT

A radio data communication apparatus includes first antennas, modulation circuits, an oscillating circuit, a switch circuit, a memory, and a control circuit. The first antennas perform a one-to-one radio communication with second antennas of IC tags having different communication frequencies. The one-to-one radio communication is carried out based on a resonance frequency uniquely assigned to each one of combinations between the first antennas and the second antennas. The memory stores communication information of each IC tag, including an assigned resonance frequency. The control circuit reads a resonance frequency assigned to a second antenna belonging to a target IC tag, generates the control signal such that the switch circuit selects a specific carrier wave having a frequency substantially equal to the resonance frequency read from the memory, and transmits the specific carrier wave and data to be transmitted in synchronism with each other to a corresponding modulating circuit.

BACKGROUND

1. Field

The present specification describes an IC-tag read-write apparatus, andmore particularly to an IC-tag read-write apparatus capable ofperforming a stable radio data communication with an IC tag.

2. Discussion of the Background

A typical structure of a background IC (integrated circuit) tagread-and-write apparatus 100 is illustrated in FIG. 1. The backgroundIC-tag read-and-write apparatus 100 communicates with a plurality of ICtags including an IC tag 110 and an IC tag 120 by performing a data readand write operation using radio waves. The background IC-tag read-writeapparatus 100 of FIG. 1 includes an antenna ANTa, an oscillating circuit(OSC) 101, a controlling circuit (CONT) 102, and a signal modulatingcircuit (MOD) 103. The IC tag 110 of FIG. 1 includes an antenna ANTb1and a signal modulating circuit (MOD) 111. The IC tag 120 of FIG. 1includes an antenna ANTb2 and a signal modulating circuit (MOD) 121.

The oscillating circuit 101 generates and outputs a carrier wave toperform a radio communication with the IC tags such as the IC tags 110and 120. The frequency of the carrier wave is generally 13.56 MHz. Forsome special applications, it may be lower in a range of from 120 kHz to500 kHz, or even a microwave of 2.4 GHz.

In a case of writing data into the IC tag 110, for example, thebackground IC-read read-write apparatus 100 conducts the operations inthe following manner. The controlling circuit 102 receives the carrierwave from the oscillating circuit 101 and performs an input and outputcontrol of a data signal to be superimposed on the carrier wave. Thesignal modulation circuit 103 receives the carrier wave and data signaloutput from the controlling circuit 102 and conducts a signal modulationto the carrier wave in accordance with the data signal. The modulatedsignal is transmitted by radio through the antenna ANTa. The IC tag 110receives the radio signal sent from the background IC-tag read-writeapparatus 100 and demodulates the received signal with the signalmodulation circuit 111.

In a case of reading data front the IC tag 110, for example, thebackground IC-read read-write apparatus 100 conducts the operations inthe following manner. The background IC-tag read-write apparatus 100sends a select command and a read command to both IC tags 110 and 120.The select command is to select the IC tag 110, for example, and theread command is to instruct the selected IC tag to output the datadesired. Upon receiving the select and read commands, the IC tag 110 isactivated and modulates the carrier wave with the signal modulationcircuit 111. Then, the IC tag 110 sends the data requested by the readcommand and transmits by radio the carrier wave together with therequested data through the antenna ANTb1. The background IC-tagread-write apparatus 100 receives the radio signal with the antennaANTa, demodulates the received signal, and retrieves the data requested.In this event, the IC tag 120 is not selected and is not activated, sothat it does not output the data desired by the read command.Accordingly, to read data from the IC tag 120, for another example, thebackground IC-tag read-write apparatus 100 needs to send a selectcommand to the IC tag 120 before the read command so as to select the ICtag 120.

SUMMARY

This patent specification describes a novel radio data communicationapparatus. In one example, a novel radio data communication apparatusincludes a plurality of first antennas, a plurality of modulationcircuits, an oscillating circuit, a switch circuit, a memory, and acontrol circuit. The plurality of first antennas are configured toperform a one-to-one radio communication with a plurality of secondantennas of IC tags having communication frequencies different from eachother. The one-to-one radio communication being carried out based on aresonance frequency uniquely assigned to each one of combinationsbetween, the plurality of first antennas and the plurality of secondantennas. The plurality of modulation circuits are connected to theplurality of first antennas on a one-to-one basis. Each one of theplurality of modulation circuits is configured to perform a modulationfunction and a demodulation function. The modulation function modulatesa carrier wave in accordance with data to be transmitted andtransmitting the modulated carrier wave to a specific IC tag among theplurality of IC tags through a corresponding one of the plurality offirst antennas. The demodulation function demodulates a modulatedcarrier wave which has been sent from a specific IC tag out of theplurality of IC tags via a corresponding one of the plurality of firstantennas. The oscillating circuit is configured to generate and output aplurality of carrier waves having frequencies different from each other.The frequencies are predetermined in accordance with a specific factor.The switch circuit is configured to exclusively select and output one ofthe plurality of carrier waves output from the oscillating circuit inaccordance with a control signal input thereto. The memory storescommunication information of each one of the plurality of IC tags,including a resonance frequency assigned thereto. The control circuit isconfigured to read from the memory a specific resonance frequencyassigned to one of the plurality of second antennas belonging to atarget IC tag among the plurality of IC tags, to generate the controlsignal such that the switch circuit selects, from among the plurality ofcarrier waves, a specific carrier wave having a frequency, out of thepredetermined frequencies, substantially equal to the specific resonancefrequency read from the memory, and to transmit the specific carrierwave selected by the switch circuit and data to be transmitted insynchronism with each other a corresponding one of the plurality ofmodulating circuits.

The specific factor for predetermining the frequencies may includeenvironmental conditions of places where the plurality of IC tags aremounted.

The specific factor for predetermining the frequencies may includematerials of places where the plurality of IC tags are mounted.

The control circuit may be configured to generate the control signalsuch that the switching circuit selects a carrier wave having arelatively low frequency when a place where the plurality of IC tags ismade of metal or conductive material and a carrier wave having arelatively high frequency when the place is made of non-metal ornon-conductive material.

Each one of the plurality of first antennas may be configured to have afrequency substantially equal to a specific resonance frequency of acorresponding one of the plurality of second antennas and is arrangedclose to the corresponding one of the plurality of second antennas.

This patent specification further describes a novel data communicationapparatus. In one example, a novel data communication apparatus includesat least one component and a radio data communication mechanism. The atleast one component performs a predetermined function and to which atleast one IC tag is installed. The radio data communication mechanismincludes a plurality of first antennas, a plurality of modulationcircuits, an oscillating circuit, a switch circuit, a memory, and acontrol circuit. The plurality of first antennas are configured toperform a one-to-one radio communication with a plurality of secondantennas of IC tags having communication frequencies different from eachother. The one-to-one radio communication being carried out based on aresonance frequency uniquely assigned to each one of combinationsbetween the plurality of first antennas and the plurality of secondantennas. The plurality of modulation circuits are connected to theplurality of first antennas on a one-to-one basis. Each one of theplurality of modulation circuits is configured to perform a modulationfunction and a demodulation function. The modulation function modulatesa carrier wave in accordance with data to be transmitted andtransmitting the modulated carrier wave to a specific IC tag among theplurality of IC tags through a corresponding one of the plurality offirst antennas. The demodulation function demodulates a modulatedcarrier wave which has been sent from a specific IC tag out of theplurality of IC tags via a corresponding one of the plurality of firstantennas. The oscillating circuit is configured to generate and output aplurality of carrier waves having frequencies different from each other.The frequencies are predetermined in accordance with a specific factor.The switch circuit is configured to exclusively select and output one ofthe plurality of carrier waves output from the oscillating circuit inaccordance with a control signal input thereto. The memory storescommunication information of each one of the plurality of IC tags,including a resonance frequency assigned thereto. The control circuit isconfigured to read from the memory a specific resonance frequencyassigned to one of the plurality of second antennas belonging to atarget IC tag among the plurality of IC tags, to generate the controlsignal such that the switch circuit selects, from among the plurality ofcarrier waves, a specific carrier wave having a frequency, out of thepredetermined frequencies, substantially equal to the specific resonancefrequency read from the memory, and to transmit the specific carrierwave selected by the switch circuit and data to be transmitted insynchronism with each other a corresponding one of the plurality ofmodulating circuits.

Each one of the plurality of first antennas may be configured to have afrequency substantially equal to a specific resonance frequency of acorresponding one of the plurality of second antennas and is arrangedclose to the corresponding one of the plurality of second antennas.

At least one of the plurality of first antennas corresponding to the atleast one IC tag may be mounted to a member to which the at least one ICtag is mounted.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is an illustration of a background IC-tag read-write apparatus;

FIG. 2 is an illustration of an IC-tag read-write apparatus according toan embodiment;

FIGS. 3 and 4 are illustrations of IC-tag read-write apparatusesaccording to other embodiments which communicate with a plurality of ICtags; and

FIG. 5 is an illustration of an apparatus containing the IC-tagread-write apparatus of FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In describing preferred embodiments illustrated in the drawings,specific terminology is employed for the sake of clarity. However, thedisclosure of this patent specification is not intended to be limited tothe specific terminology so selected and it is to be understood thateach specific element includes all technical equivalents that operate ina similar manner. Referring now to the drawings, wherein like referencenumerals designate identical or corresponding parts throughout theseveral views, particularly to FIG. 2, an IC-tag (integrated circuittag) read-write apparatus 1 according to an exemplary embodiment isexplained.

In FIG. 2, the IC-tag read-write apparatus 1 includes an oscillator(OSC) 2, a switch circuit (SWITCH) 3, a controller (CONT) 4, a memory 5,a plurality of modulation circuits (MOD) MD1 to MDn, and a plurality ofantennas ANT1—ANTn. Suffix n given to MD and ANT is a positive integergreater than 1.

FIG. 2 also illustrates a plurality of IC (integrated circuit) tags IT1to ITn, in which a suffix n given to IT is a positive integer greaterthan 1. The plurality of IC tags IT1 to ITn include a plurality ofmodulation circuits (MOD) MDa1 to MDan, respectively, and a plurality ofantennas ANTa1 to ANTan, respectively. Suffix n given to MDa and ANTa isa positive integer greater than 1.

In the IC-tag read-write apparatus 1 of FIG. 2, the oscillator 2generates a plurality of carder waves including carrier waves S1 to Smhaving frequencies F1 to Fm different from each other, in which thesuffix in provided to S and F is a positive integer greater than 1 andequal to or smaller than n. The switch circuit 3 selectively outputs oneof the carrier waves output from the oscillator 2 in accordance with acontrol signal input from the controller 4. The controller 4 controlsthe switching operation of the switch circuit 3 through the controlsignal, and also controls input and output of the data signal to besuperimposed on the carrier wave.

As described above, the switch circuit 3 exclusively selects one of thecarrier waves S1–Sm, output from the oscillator 2, in accordance withthe control signal received from the controller 4 and outputs theselected carrier wave to the controller 4. The memory-5 stores datarepresenting parameters including communication frequencies andcommunication protocols pertinent to the IC tags IT1–ITn. The controller4 selects one of the carrier waves based on the data stored in thememory, and controls the switch circuit 3, to output the selectedcarrier wave.

Each of the modulation circuits MD1–MDn receives the carrier wave andthe data signal, output from the controller 4, performs a predeterminedmodulation to the carrier wave in accordance with the data signal, andsends the modulated signal to the corresponding antenna.

On the other hand, each of the modulation circuits MD1-MDn performs apredetermined demodulation to a signal received from outside via thecorresponding antenna out of the antennas ANT1–ANTn and outputs aresultant demodulated signal to the controller 4. The controller 4extracts the desired data from the demodulated signal.

In the IC tags IT1–ITn, each of the antennas ANTa1–ANTan is arranged ata position relatively close to the corresponding one of the antennasANT1–ANTn. An antenna ANTk, one of the plurality of antennas ANT1 toANTn of the IC-tag read-write apparatus, and an antenna ANTak, one ofthe plurality of antennas ANTa1 to ANTan of the IC tags, have aresonance frequency which is commonly set to a k-th frequency. In thisrespect, the IC tag ITk is basically the one communicating with theIC-tag read-write apparatus 1 via the antenna ANTk. The suffix kprovided to ANT and ANTa is a positive integer greater than 1 andsmaller than n.

However, it is possible that more than one antennas of the IC tag sidecan be disposed in the vicinity of one antenna of the IC-tag read-writeapparatus side. Thus, it becomes possible that a pair of the modulationcircuit and the antenna of the IC-tag read-write apparatus sidecommunicates with the number of IC tags, when the IC tags allows thecommunications with the same frequency.

In communications of the IC-tag read-write apparatus 1 with the IC tagITk, the controller. 4 reads data stored in the memory 5 for theresonance frequency of the IC tag ITk and sends the read data to theswitch circuit 3. The switch circuit 3 selects a carrier wave having afrequency in accordance with such data sent from the controller 4 andsends the selected carrier wave to the controller 4. The controller 4further reads from the memory 5 the communication protocols data forselecting the IC tag ITk and data representing the communicationsprotocols, and sends the input carrier wave together with the read datato the modulation circuit MDk.

The modulation circuit MDk performs the predetermined modulation to thecarrier wave in accordance with the data signal and sends the resultantsignal to the antenna ANTk. The signal thus transmitted by radio wavesfrom the antenna ANTk is received by the antenna ANTak of the IC tagITk, and the received signal is demodulated by the modulation circuitMDak.

It is possible to configure the controller 4 to prohibit any otherdifferent antenna from transmitting by radio a carrier wave having thefrequency same as the one transmitted from the antenna ANTk.

In a case the controller 4 does not have such a prohibition function asdescribed above, the signal sent to the modulation circuit MDk may alsobe sent to another modulation circuit in the IC-tag read-write apparatus1 and accordingly the carrier wave having the K-th frequency may betransmitted by radio from another antenna which is different from theantenna ANTk. However, the resonance frequency of such another antennais not the k-th frequency and therefore the radio waves transmitted froman antenna other than the antenna ANTk is weak for the radiocommunication.

Further, the antennas ANTa1–ANTan are in a similar situation. Namely,the resonance frequencies of other antennas than the ANTak are not thek-th frequency and therefore the radio waves transmitted from otherantennas than the antenna ANTak are weak for the radio communications.

In order to communicate with an IC tag other than the IC tag ITk (e.g.,the IC tag IT2), the controller 4 instructs the switch circuit 3 toselect the carrier wave S2 having the second frequency corresponding tothe IC tag IT2. After the selection, the controller 4 sends therequisite data stored in the memory 5 together with the carrier wave S2of the second frequency to the modulation circuit MD2. The requisitedata represents parameters including the selection data and thecommunication protocols pertinent to the IC tag IT2. Thus, the IC-tagread-write apparatus 1 achieves the communications with a selected ICtag, i.e., the IC tag IT2. In this way, the IC-tag read-write apparatus1 can selectively communicate with any one of the IC tags ITa1–ITan.

Since the communications rate between the IC tag and the IC-tagread-write apparatus is increased with an increase of carrier wavefrequency, it is preferable to change the frequency used forcommunications between the IC tag and the IC-tag read-write apparatus inaccordance with the environmental factors surrounding the IC tag or arequired communications frequency.

When the place for mounting the IC tag has a metal or conductivesurface, it is preferable to use a low frequency in the range of from120 kHz to 500 kHz, which is insusceptible to such material. On theother hand, when the IC tag is mounted on a place of a nonmetal orelectrical insulating material, it is preferable to use a high frequencysuch as 13.56 MHz which allows a high speed communication.

It is also possible to use the frequency such as 900 kHz or 2.4 GHz, forexample, depending upon the required communications speed and theenvironments with respect to the place for mounting the IC tag.

Referring to FIG. 3, an IC-tag read-write apparatus 10 according toanother embodiment is explained. The IC-tag read-write apparatus 10 ofFIG. 3 is similar to the IC-tag read-write apparatus 1, except for anoscillator 12 and a frequency divider 13. The oscillator 12 generates acarrier wave S1 and outputs it to the switch circuit 3 and the frequencydivider 13. The frequency divider 13 receives the carrier wave S sentfrom the oscillator 12, and divides the carrier wave S1 using aplurality of different frequencies into a plurality of carrier waves S2to Sm having frequencies different from each other. As a result, thecarrier waves S2 to Sm are output from the frequency divider 13 and aresent to the switch circuit 3. Thus, in the IC-tag read-write apparatus10, the switch circuit 3 can receive the carrier waves S1 to Sm, as inthe case of the IC-tag read-write apparatus 1 shown in FIG. 2.

After thus supplying the carrier waves S1 to Sm to the switch circuit 3,the IC-tag read-write apparatus 10 performs the operations similar tothose of the IC-tag read-write apparatus 1 of FIG. 2 to read data fromand to write data to the IC tags IT1 to ITn.

As an alternative, the operations performed by the the frequency divider13 and the switch circuit 3 may be conducted by a software program. Inthis case, the IC-tag read-write apparatus may be embodied as an IC-tagread-write apparatus 20 having a structure as illustrated in FIG. 4. Asillustrated in FIG. 4, the IC-tag read-write apparatus 20 is similar tothe IC-tag read-write apparatus 10 of FIG. 3, except for a controller 24which replaces the frequency divider 13, the switch circuit 3, and thecontroller 4.

In the IC-tag read-write apparatus 20 of FIG. 4, the controller 24 isconfigured to receive the carrier wave S1 output from the oscillator 22and to generate the carrier waves S2-Sm. When the IC-tag read-writeapparatus 20 communicates with the IC tag ITk, in which k is a positiveinteger equal to or greater than 1 and equal to or smaller than n, thecontroller 24 reads data of resonance frequency of the IC tag ITk storedin the memory 5 and generates a carrier wave having the resonancefrequency read from the memory 5. The controller 24 further reads selectdata representing the IC tag ITk and also information includingcommunication protocols, from the memory 5. Then, the controller 24sends the carrier wave with the resonance frequency and the data readfrom the memory 5 to the modulation circuit MDk. For example, when thecarrier wave having the resonance frequency of the IC tag ITk stored inthe memory 5 is the carrier wave S, the controller 24 sends the selectdata of the IC tag ITk together with the information including thecommunications protocols read from the memory 5 to the modulationcircuit MDk.

Referring to FIG. 5, an exemplary apparatus 30 is explained, whichemploys the IC-tag read-write apparatus according to the presentembodiment and conducts the radio data communications using the IC-tagread-write apparatus. The apparatus 30 can be a digital copier, aprinter, or the like capable of performing the radio data communicationsusing the IC-tag read-write apparatus 1 of FIG. 2, for example. TheIC-tag read-write apparatus used may alternatively be one of those shownin FIGS. 3 and 4, for example. In FIG. 5, a reference numeral 6 denotesa circuit unit representing the oscillator 2, the switch circuit 3, thecontroller 4, and the memory 5 of the IC-tag read-write apparatus 1. Ina case the IC-tag read-write apparatus 10 of FIG. 3 is applied, thecircuit unit 6 represents the oscillator 12, the frequency divider 13,the switch circuit 3, the controller 4, and the memory 5. In a case theIC-tag read-write apparatus 20 of FIG. 4 is applied, the circuit unit 6represents the oscillator 12, the controller 24, and the memory 5.

In FIG. 5, two sets of the antennas AN1 and ANT2 and the IC tages IT1and IT2 are representatively illustrated for the sake of simplicity;however, more than two sets can be applied since the IC-tag read-writeapparatus 1 includes the antennas ANT1 to ANTn.

As illustrated in FIG. 5, the apparatus 30 includes a mounting member 31and two components 32 and 33. It is possible to provide more componentsthan the two components 32 and 33. The components 32 and 33 are thosehaving status parameters varying over time, namely, toner containers,for example. Status parameters of the components 32 and 33 which variesover time include a remaining amount of toner in the toner container,for example. These status parameters are monitored to maintain theapparatus 30 in an operable condition. To monitor the parameters, the ICtags IT1 and IT2 are fixed to the components 32 and 33, respectively,and the IC-tag read-write apparatus 1 is arranged to receive informationof the status parameters of the components 32 and 33 through the IC tagsIT1 and IT2 via radio data communications.

As illustrated in FIG. 5, the component 32 is mounted to the mountingmember 31 and the position of the IC tag IT1 fixed to the component 32is preferably close to the mounting member 31. The antenna ANT1 of theIC-tag read-write apparatus 1 communicating with the IC tag IT1 is fixedto the mounting member 31 at a place as close as possible to the IC tagIT1. In a similar manner, the IC tag IT2 and the antenna ANT2 of theIC-tag read-write apparatus 1 are mounted to the component 33 and theMounting member 31, respectively.

When the components 32 and 33 are made of a nonmetal or electricalinsulating material, the IC-tag read-write apparatus 1 can select arelatively high frequency such as 13.56 MHz or the like as the firstfrequency for the communication with the IC tags IT1 and IT2 so as toperform a high speed data transmission. When the components 32 and 33are made of a metal or conductive material, a relatively low frequencyinsusceptible to such a metal or conductive material is selected in therange of from 120 kHz to 500 kHz. It is further possible to use otherfrequency than the above, such as 900 kHz or 2.4 GHz, for example,depending upon a situation required based on the material of thecomponents 32 and 33 and the data communication speed.

Thus, in the apparatus 30, the IC-tag read-write apparatus 1 canselectively use one of the carrier waves susceptible to the environmentssurrounding the IC tags IT1 and IT2, for example. Accordingly, itbecomes possible to make sure that the IC-tag read-write apparatus 1properly performs the radio data communications with the target IC tags.Furthermore, when the influences by the environments are negligible, theIC-tag read-write apparatus 1 can use a carrier wave having a relativelyhigh frequency so as to be able to increase the radio datacommunications speed.

Numerous additional modifications and variations are possible in lightof the above teachings. It is therefore to be understood that within thescope of the appended claims, the disclosure of this patentspecification may be practiced otherwise than as specifically describedherein.

This patent specification is based on Japanese patent application No.2001-015687 filed on Jan. 23, 2004, in the Japan Patent Office, theentire contents of which are incorporated by reference herein.

1. A radio data communication apparatus, comprising: a plurality offirst antennas configured to perform a one-to-one radio communicationwith a plurality of second antennas of IC tags having communicationfrequencies different from each other, the one-to-one radiocommunication being carried out based on a resonance frequency uniquelyassigned to each one of combinations between the plurality of firstantennas and the plurality of second antennas; a plurality of modulationcircuits connected to the plurality of first antennas on a one-to-onebasis, and each configured to perform a modulation function formodulating a carrier wave in accordance with data to be transmitted andtransmitting the modulated carrier wave to a specific IC tag among theplurality of IC tags through a corresponding one of the plurality offirst antennas and a demodulation function for demodulating a modulatedcarrier wave which has been sent from a specific IC tag out of theplurality of IC tags via a corresponding one of the plurality of firstantennas; an oscillating circuit configured to generate and output aplurality of carrier waves having frequencies different from each other,the frequencies being predetermined in accordance with a specificfactor; a switch circuit configured to exclusively select and output oneof the plurality of carrier waves output from the oscillating circuit inaccordance with a control signal input thereto; a memory storingcommunication information of each one of the plurality of IC tags,including a resonance frequency assigned thereto; and a control circuitconfigured to read from the memory a specific resonance frequencyassigned to one of the plurality of second antennas belonging to atarget IC tag among the plurality of IC tags, to generate the controlsignal such that the switch circuit selects, from among the plurality ofcarrier waves, a specific carrier wave having a frequency, out of thepredetermined frequencies, substantially equal to the specific resonancefrequency read from the memory, and to transmit the specific carrierwave selected by the switch circuit and data to be transmitted insynchronism with each other to a corresponding one of the plurality ofmodulating circuits, wherein the predetermined frequencies are withinthe radio wave spectrum.
 2. A radio data communication apparatus ofclaim 1, wherein the specific factor for predetermining the frequenciesincludes enviromnental conditions of places where the plurality of ICtags are mounted.
 3. A radio data communication apparatus of claim 1,wherein the specific factor for predetermining the frequencies includesmaterials of places where the plurality of IC tags are mounted.
 4. Aradio data communication apparatus of claim 1, wherein the controlcircuit is configured to generate the control signal such that theswitching circuit selects a carrier wave having a relatively lowfrequency when a place where the plurality of IC tags is made of metalor conductive material and a carrier wave having a relatively highfrequency when the place is made of non-metal or non-conductivematerial.
 5. A radio data communication apparatus of claim 1, whereineach one of the plurality of first antennas is configured to have afrequency substantially equal to a specific resonance frequency of acorresponding one of the plurality of second antennas and is arrangedclose to the corresponding one of the plurality of second antennas.
 6. Aradio data communication apparatus of claim 1, wherein the predeterminedfrequencies are in a range of 3 kHz to 300 GHz.
 7. A radio datacommunication apparatus of claim 1, wherein the frequency of thespecific carrier is in a range of 120 kHz to 2.4 kHz.
 8. A radio datacommunication apparatus of claim 1, wherein the frequency of thespecific carrier is in a range of 120 kHz to 900 kHz.
 9. A radio datacommunication apparatus of claim 1, wherein the frequency of thespecific carrier is in a range of 120 kHz to 500 kHz.
 10. A radio datacommunication apparatus of claim 1, wherein the frequency of thespecific carrier is in a range of 900 kHz to 2.4 GHz.
 11. A datacommunication apparatus, comprising: at least one component forperforming a predetermined function and to which at least one IC tag isinstalled; and a radio data communication mechanism which comprises: aplurality of first antennas configured to perform a one-to-one radiocommunication with a plurality of second antennas of IC tags havingcommunication frequencies different from each other, the IC tagsincluding the at least one IC tag, and the one-to-one radiocommunication being carried out based on a resonance frequency uniquelyassigned to each one of combinations between the plurality of firstantennas and the plurality of second antennas; a plurality of modulationcircuits connected to the plurality of first antennas on a one-to-onebasis, and each configured to perform a modulation function formodulating a carrier wave in accordance with data to be transmitted andtransmitting the modulated carrier wave to a specific IC tag among theplurality of IC tags through a corresponding one of the plurality offirst antennas and a demodulation function for demodulating a modulatedcarrier wave which has been sent from a specific IC tag out of theplurality of IC tags via a corresponding one of the plurality of firstantennas; an oscillating circuit configured to generate and output aplurality of carrier waves having frequencies different from each other,the frequencies being predetermined in accordance with a specificfactor; a switch circuit configured to exclusively select and output oneof the plurality of carrier waves output from the oscillating circuit inaccordance with a control signal input thereto; a memory storingcommunication information of each one of the plurality of IC tags,including a resonance frequency assigned thereto; and a control circuitconfigured to read from the memory a specific resonance frequencyassigned to one of the plurality of second antennas belonging to atarget IC tag among the plurality of IC tags, to generate the controlsignal such that the switch circuit selects, from among the plurality ofcarrier waves, a specific carrier wave having a frequency, out of thepredetermined frequencies, substantially equal to the specific resonancefrequency read from the memory, and to transmit the specific carrierwave selected by the switch circuit and data to be transmitted insynchronism with each other to a corresponding one of the plurality ofmodulating circuits.
 12. A data communication apparatus of claim 11,wherein each one of the plurality of first antennas is configured tohave a frequency substantially equal to a specific resonance frequencyof a corresponding one of the plurality of second antennas and isarranged close to the corresponding one of the plurality of secondantennas.
 13. A data communication apparatus of claim 11, wherein atleast one of the plurality of first antennas corresponding to the atleast one IC tag is mounted to a member to which the at least one IC tagis mounted.